This invention relates to surgical apparatus and procedures in general, and more particularly to a removable cannula useful during arthroscopic or laparoscopic surgery for protecting other apparatus or tissue from damage during insertion of sharp instruments into a patient""s body or joint cavity.
There are at least two reasons for the need for a novel removable protective cannula to protect other apparatus or tissue from damage during insertion of sharp instruments into a patient""s body or joint cavity.
Firstly, cylindrical cannulas, usually made of plastic and sometimes made of metal, are inserted through puncture sites into body or joint cavities. These portal cannulas allow for easy insertion and withdrawal of instruments into and out of the joint or body cavity. There is usually a rubber diaphragm or valve in the proximal part of the cannula to prevent egression of fluid or gas out of the cavity. During laparoscopic or arthroscopic surgery, oftentimes sharp instruments such as suture passers or knives are inserted into the joint or body cavity through the portal cannulas. The sharp distal end of the instrument can cause damage to the diaphragm. Thus, there is a need for a protective apparatus to prevent damage to the rubber diaphragm or valve of the portal cannula during insertion of sharp instruments through the portal cannulas.
Secondly, the maneuverability of instruments inserted through portal cannulas can be restricted due to the bulkiness of the portal cannula itself. This restriction of the maneuverability of surgical instruments can be particularly severe if portal cannulas are clustered close together. Therefore, some surgeons prefer to insert surgical instruments into the body cavity without the use of a portal cannula. However, inserting a sharp instrument through a previous puncture site may inadvertently create new insertion tracks and run the risk of damage to body structures such as nerves or blood vessels. Therefore, there is a need for a protective cannula that protects the surrounding soft tissue during insertion of the sharp instrument, with the protective cannula being removable after the sharp instrument is inserted into the cavity.
A removable protective cannula is disclosed for use in surgery to prevent damage to a portal cannula or tissue during insertion of a sharp instrument. The removable protective cannula preferably comprises a cylindrical tube, a handle attached at the proximal end of the cylindrical tube, and a slot extending along the length of the cylindrical tube.
In one embodiment of the invention, the width of the slot occupies less than half the circumference of the cylindrical tube.
In another embodiment of the invention, the cylindrical tube has a rounded distal end.
In still another embodiment of the invention, the slot extends substantially the whole diameter of the rounded distal end.
In still yet another embodiment of the invention, the slot is diametrically opposed to the handle.